Free-standing masonry walls typically are constructed of concrete blocks or the like, in running courses, using mortar between the courses and between the ends of each of the blocks. Concrete blocks typically have one or more voids extending through them in the vertical direction to create vertical voids through the walls. Reinforcing bars are placed in these voids for inclusion within a continuous vertical grout column, in accordance with building code standards. Such grout columns typically are placed approximately four feet apart along the length of the wall. Normally, the voids in blocks, which are not involved in the formation of a vertical grout column, are left empty. To provide improved thermal insulation qualities for such masonry walls, the empty voids in masonry block walls may be filled with insulation to reduce the thermal energy transfer between the inner and outside walls of the blocks, and thus of the free-standing wall, which is formed from the blocks.
U.S. Pat. No. 4,769,964 to Johnson is directed to a self-aligned and self-leveled, insulated drystack block wall construction. In the construction blocks disclosed in this patent, insertable cores of insulating material are placed in the voids or openings in the blocks to improve the interlocking of the blocks in forming a wall, and to reduce thermal energy transfer between the inner and outer sides or walls of the blocks used to form the wall. In the Johnson patent, the inserts also assist in self-alignment and self-leveling of a running course of block used to construct the wall. To meet building codes requiring a continuous vertical grout column at periodic intervals along the running length of the wall, various ones of the insulation cores are eliminated from the blocks to form a continuous vertical void in the standing wall. Reinforcing bar then is inserted into the voids established by the removal of the cores, and grout is used to fill the voids to establish the required grout cell. These grout cells are formed in a conventional manner, after erection of the wall, to produce the required structural reinforcement.
In the construction of masonry block or concrete block walls, of the type disclosed in the above mentioned Johnson patent, no pre-stressing or post-stressing of the wall thus formed is employed. The structural rigidity is provided by the reinforcing bar and grout columns formed in the walls subsequent to their erection. The regions where the grout columns are formed have a greater thermal conductivity (and, therefore, provide less insulating qualities) than the regions between the grout columns, where either insulating inserts are provided, or air-filled voids exist.
It is desirable to provide a masonry wall of concrete wall construction which incorporates the advantages of the insulating inserts of the Johnson patent, and which provides the reinforcement typically produced by grout columns, by continuously utilizing installed stress in the wall at periodic intervals along the wall.